Black Hills Geology and Caves
http://www.rushmorecave.com/cave-education/pahasapa-limestone-outcrop-belt/

Beautiful Rushmore Cave


This page describes the formation of the limestone caves in the Black Hills. The geological processes that fashioned and preserved the caves are briefly explained.

This resource is referenced here:
Subject: Geoscience:Geology:Historical Geology
Resource Type: Scientific Resources:Overview/Reference Work
Topics: Time/Earth History